I got in my truck to go to church this morning, and needless to say I didn't make it. It started up just fine, and I pulled around and about 20 or 30 yards later it quit on me. I was able to make it into the second (my) driveway away from the house to park it at least. It just quit. Now when I turn the key, I don't get a whir from the fuel pump priming the system. I'm thinking that it is a problem with the fuel pumps, then. Only problem is, I don't know where to start. I'm also relativly tight on cash right now, so I can't afford to throw money at it and get things fixed, you know?

As to the codes part, I can't seem to find proper codes for my truck. I had one website that was telling me the codes, and none of the codes that my truck spit out (3 apparently) have anything to do with her. Codes run were 67, 96, and hte last I believe was a memory code because it came out last almost before it repeated the first two then stopped, 32. Could somebody point me to a site that has the codes, or look them up for me? I thought maybe I screwed it up..but 79 and 66 don't apply to my truck either. Please, any help would be GREATLY appreciated. As to the codes, and also how I can check to determine which pump may be bad, if either.

The truck is an 1989 F150 with the 300-6 engine, M5OD transmission, dual tanks (19/17) with an external high-volume pump and an in-tank booster pump. My rear tank has a leak, but I am going to try to get into town and grab myself a couple gallons of gas to dump in and see if I can get running off of the rear one at least. Thanks!

I did searches...but couldn't find info I needed on diagnosing which pump...

 

I assume you have already checked all the fuses and relays. When you turn the key do all the other electronic components work other than not hearing the fuel pump kick on?

T. Roberts
UFD Local 1147

 

I Would Start With Your Fuel Pump Relay. Also Buying A Chilton's Or Haynes Repair Manual From An Auto Parts Store Will Help Out A Lot.

 

Everything else electrical appears to be working. The only thing that seems to have changed is the lack of that noise.

I plan on getting the manual at the next possible chance. I don't know if it is the fuel pump relay or not. Right now I believe it is the external fuel pump, or a bit further out there - possibly the TFI module from talking with my chapter president. I'm still leaning towards external fuel pump. I wouldn't mind if it were the TFI module..its a bit cheaper =P. I'll start working on these problems on Teusday. Tomorrow...they won't be open, which kinda sucks but what can you do.

Fuel Pump Relay
External Fuel Pump
TFI Module

What else do I need to look at?

 

Run a hot wire from the battery to the external pump. If it runs it is most likely the relay. If it doesn't run then the pump is bad.

T. Roberts
UFD Local 1147

 

Here's a site to reference for codes: http://fordfuelinjection.com/codes.html .

96 is the code I would be concerned with - it is telling you there is a failure in the fuel pump secondary circuit. Could be a bad pump, bad relay, or the inertia switch could have tripped. Get a wiring diagram (Haynes manual will be fine) and then jump power to FP wires where the relay connects to see if the pumps come on. If they do, then it's likely the relay. If they don't, check the inertia switch under the dash first, then if you still have nothing, I would listen very carefully to see if you can hear the in-tank pumps running. If the high pressure pump failed, then the truck will not run, like you describe. This should be enough to get you pointed in the right direction at least.

 

I hooked up a new external fuel pump, kinda mock up style right beside the old one. When I turned the key, still didn't have anything. So, since I hadn't removed the old one, I just hooked it back up since it would appear that the pump wasnt bad.

I also got out my test light (duh..a bit late) and low and behold - when I clipped onto the fuel pump and dropped the head onto the pos wire, with my uncle turning the key on and off like he was priming it in the winter...there's no voltage. Nothing inline, not even the slightest blip of light from the test light. So...no current. What does this mean it could be? Tracing back from the external fuel pump, it could be the Fuel Pump Relay or the Inertia switch? I found my intertia switch finally, and when I tried to press it, it was already down. I could lift it up with a screw driver (the button) and press it down again. Does down mean good? When it trips, does the button pop up for you to depress again to activate the circuit? I tried to run BACK to return the pump and buy a relay, but after my 20 minute drive there they were closed (he told me I had 25 minutes...). We'll see tomorrow.

I don't know if I mentioned, but I put gas into the back tank and flipped back to it, and I cranked away with no results. So it SHOULDN'T be the in-tank pumps, I can't see both of them burning out at the same time. Especially when the rear pump isn't in use due to a small hole towards the top of the tank.

Thanks for your posts...any further ideas? Comments?

 

first have someone listen under the hood while you turn the key for the fuel pump relay. even if the in tank pump goes bad the truck should at least run roughly, at least mine does. if you here the relay use a meter and check for voltage going in and out of the relay. if there is the check for broken power line going to the pump.
hope this helps chrono

 

I put on a new fuel pump relay and it didn't change the status quo at all. My truck still just cranks and cranks.

To summarize, I've checked the ext fuel pump with a new one mocked up to it, and the new one wasn't operable either. New Fuel Pump Relay, nothing changes. I have no voltage to my ext fuel pump. I have a code being thrown because of that no voltage. My inertia switch button is still down, which I'm assuming means that it hasn't "broken" the circuit. I can hear some slight action in the back of the truck, which I am pretty sure is the sound of whichever rear fuel pump is active.

Where do I look now? TFI Module? Would it cause symptoms like this? What about the Fuel Tank Selector? Would it do this? Fuel Filter?

I'm going to run a hot wire down to the fuel pump next chance I get, so I can see if that's where the problem is. Please, if anybody has any other ideas or instructions...I have till Monday to get this fixed then I'm riding 20 miles on my 500cc ATV to make it to work and school -

 

i couldnt figure my fuel problem out either so i just ran a hot line off of the fuel relay and then to a switch on the dash so i get power to the switch with the key on and only when the key is on and i can turn it off when im just sitting there listtening to the radio or whatever.